1. Field of the Invention
This invention relates to a vehicle for storing and feeding loose mined material and more particularly to a self-propelled material storage and feeding vehicle having a movable hopper positioned within a fixed storage hopper in which the loose material is deposited and fed to a scroll-breaker on the vehicle by advancement of the movable hopper.
2. Description of the Prior Art
Conventional modern continuous mining machines move progressively and continuously into a mine vein. As an integral part of such machines, a rearwardly moving conveyor accepts mined material adjacent the face of the mine and transports it rearwardly through the mining machine for discharge at the rear end thereof. During the operation of the mining machine, the flow of this material emerging from the mining machine conveyor is continuous.
Material emerging from the mining machine is ultimately placed in a haulage vehicle, such as a shuttle car or a haulage vehicle as described in U.S. Pat. Nos. 3,809,262 and 3,826,387 which when filled travels away from the mine area to be unloaded. The mined material is transferred from the haulage vehicle onto a section belt that transports the material out of the mine. A problem is created as a result of the mining machine at one end of the system operating continuously, while the haulage vehicle is available to accept materials only intermittently. Therefore, the haulage vehicle must transfer the loose material onto the section belt at a high rate if the mining machine is to be operated substantially continuously and thereby mine a maximum amount of material within a given time in order to avoid intermittent shutdowns during the travel and unloading period of the haulage vehicle.
At the other end of the system the section belt must operate at a lower rate than the rate of operation of the shuttle car to convey the mined material out of the mine. Therefore, it is necessary for compensation to be made in the material transporting system to permit the continuous operation of the mining machine conveyor. This is accomplished by eliminating delays in unloading the shuttle car at the section belt.
One device for compensating for the time delay created by unloading the shuttle car at the section belt is disclosed in U.S. Pat. Nos. 2,290,950, 2,637,457 and 3,064,837 wherein a storage-loading or surge machine is positioned between the mining machine and the shuttle car and is adapted to receive the mined material from the mining machine conveyor for transfer to the shuttle car. The surge machine provides storage facilities for the loose mined material during the intervals when the shuttle car is unloaded to permit continuous, uninterrupted operation of the mining machine. The surge machine includes a transport conveyor and adjustable devices by which the amount of material entering the storage area and the amount moving onto the shuttle car may be controlled. However, operation of the surge machine in this manner does not relieve the delays encountered by the shuttle car when it transfers the loose material onto a section belt.
In U.S. Pat. Nos. 3,016,204 and 3,047,125 feeder conveyors receive mined materials from a shuttle car and deliver the material at a controlled rate to a main conveyor system. U.S. Pat. No. 3,016,204 discloses a feeder-breaker unit for shattering the larger chunks of mined material into smaller pieces and depositing the smaller pieces upon the conveyor system. Hydraulic cylinders are provided for regulating the height of the conveyor so as to control the rate at which the material is discharged from the storage facility.
Material handling and storage vehicles are also disclosed in U.S. Pat. Nos. 2,637,475, 2,670,836 and 2,753,971 in which one or more conveyors transfer the material the length of the storage bin. Provision is made for regulating the speed of the conveyors to accommodate the transfer of the material through the hopper in synchronization with the shuttle car travel. For example, during the period when the material is stored, the conveyors may operate at a very slow speed to continue to transfer the material from the receiving end to the discharging end of the storage bin. However, systems employing flight conveyors for automatic termination of the discharge must be carefully coordinated with the prime movement of the shuttle car. Due to the inherent problems with flight conveyors as for example repairs to chains, sprockets and other rotating parts, this type of system is relatively inflexible.
An alternative to transporting loose material on a vehicle by a flight conveyor is disclosed in U.S. Pat. Nos. 3,809,262 and 3,826,387 which disclose a self-loading haulage vehicle consisting of a tractor unit joined by an articulated connection with a trailer unit. The trailer unit consists of three hoppers; a stationary hopper, an inner hopper having a cleaner plate which extends into the stationary hopper, and a sump hopper which extends ahead of the stationary hopper and includes a loading gate. In operation the inner hopper is extended and the sump hopper retracted with the loading gate down. The tractor trams the trailer into a pile of loose mined material so that the gate is forced under the material and into the inner hopper. The inner hopper is retracted and the tractor is trammed further into the loose material forcing the material into the stationary hopper. The vehicle makes a third pass in which the tractor again trams into the loose material and the sump hopper is extended and thus loaded. The gate is closed to complete the loading cycle.
There is need for an apparatus for the handling of loose mined material which coordinates the continuous delivery of the loose material from the mining machine onto a haulage vehicle and therefrom onto a conveyor system for movement of the material out of the mine. While it has been suggested to provide intermittent storage capability, the prior art systems require a multiplicity of flight conveyors which must be coordinated with the rate of operation of the haulage vehicle and the rate at which the material is transported by the conveyor system. It is essential that the storage and feeding vehicle be operable to receive material from a haulage unit at a high rate and discharge it to the section belt at a lower rate and thereby provide maximum efficiency without unloading delays.